Tensiometer



`lune 11, 1946.

A. L. MARKER E- r AL TENSIOMETER Filed May 23, 1944 #Lgf/9T L. Nwe/Ele@dE/mfc WEE/865K@ INVENTOR.

A? r TORA/Ey.

Patented June 11, 1946 Y TENSIOMETER Albert L. Marker and Emric W.Bergere, San Diego, Calif.

Application May 23, 1944, Serial No. 536,999

This invention relates to tensiometer.

.In the construction and maintenance of various equipment, andparticularly airplanes, it is necessary to rig them with cables, whichare maintained under a desired tension and are used for the purpose ofbracing the structural parts of the ship or for operating controls. Ineach instance it is necessary to maintain the cables, guy wires and thelike, under a predetermined minimum tension. Various types oftensiometers have been designed for this purpose. These instruments arefor the most part expensive and must be carefully handled in order toprevent injury and misadjustment of the parts. At the present time thereis in use a type of wrench which applies a predetermined amount oftorque to an object to be rotated. It has been found desirable toprovide a convenient piece of equipment with which' such a wrench may beused to perform the functions of a tensiometer and to make it possibleto quickly and accurately ascertain whether or not a cable has beendrawn sumciently tight to be under a predetermined minimum tension. Itis the principal object of the present invention, therefore, to providea tool having adjustable indicating means thereon and elements to engagea cable, and which tool may be easily assembled with av` torque set'wrench whereby the Wrench may function to indicate when a minimumdesired tension has been imposed upon the cable.

'Ihe present invention contemplates the provision of a unitary toolhaving a handle and gripping means thereon for engaging a cable at iixedpoints on one side of the cable and a movable element for engaging thecable at an intermediate point upon the opposite side of th'e cable,said element being capable of adjustment for cables of dierent diametersand being provided with means whereby a set torque wrench may beassembled temporarily with the movable element to make a tension test;

The invention is illustrated by way of example in the accompanyingdrawing in which:

.Figure 1 is a view in side elevation showng the cable engagng tool withwhich' the present invention is concerned and indicating the applicationof a set torque wrench with relation thereto.

Fig. 2 is a View of the tool taken edgewise to show the handle and theoiset position of the plate carrying cable engaging means.

Fig. 3 is a fragmentary view showing a portion of the tool as seen fromth'e opposite side indicated in Fig. 1, and more fully disclosing thexed and movable cable engaging elements.

5 Claims. (Cl. 73-144) Referring more particularly to the drawing, I0indicates a handle. This handle is formed integral with a body plate IIhere shown as having an arcuate portion I2 and a transverse portion I3,which extends laterally of the longitudinal axis of the h'andle and atopposite sides of said axis. The upper edge of the plate I I is bent atright angles to the body of the plate, as indicated at I4, and providesa stiffening land mounting member which is also at right angles to thelongitudinal. axis of the handle. Extending through the portion I3 ofthe plate adjacent the ilange and near opposite ends of thefplate arepins I5 and IG, respectively. These are disposed with their axesparallel and normal to the plane of the plate. Mounted upon the pins aresaddle blocks, I1 and I8, respectively. Each saddle block is formed withan arcuate groove I9 in its lower face to receive a cable 20, which isto be tested. The saddle blocks h'ave an upper flat face ZI againstwhich a leaf spring 22 rests.` This spring is secured to the under faceof the ange I4 by a bolt 23. Disposed in the same plane with the blocksI'I and I8 and substantially midway the distance between these blocks isa saddle block 24 which has an arcuate grooved upper face 25. Thisengages the cable 20 substantially midway between the centers of theblocks Il and I8 and rests against the diametrically opposite side ofthe cable 20 from that against which the grooves I9 of the blocks I1 andI8 rest. The lower saddle block 24 is mounted upon a pivot pin 26 havingan axis parallel to pins I5 and I5. The pin 26 extends through a slot 21in the plate I3 and is carried by the free end of a pressure lever 28.The pressure lever 28 is carried by a fulcrum pin 29 extending throughthe plate I3. A lever extension 39 is formed integral with the lever 28and is disposed at a suitable angle thereto. This extension is formed atits free end with a squared opening 3|. The squared opening 3| receivesa squared pin carried by the head of a set torque wrench, indicated bydotted lines at 32. This wrench embodies the principle disclosed in U.S. Patent No. 2,172,561 issued to Frederick P. Kruse on September 12,1939, and its details are shown generally in Patent No. 2,365,486 issuedto Harry P. Morris on December 19, 1944. It Will be understood that inthis type of wrench an adjusting plug 33 creates a desired compressionof a spring carried Within the handle of the wrench and tends to holdthe head of the wrench against rotation with relation to the wrenchhandle and body until a predetermined resistance is offered to the headof the wrench, whereby the handle sizes of cable 23 which are to betested, and when the cable 2E) is unflexed the top saddle blocks I1 andI8 and the lower saddle block 24 will be disposed so that their arcuatefaces Willccontact the cable. 31 should be in register with thegraduation on the scale 3S agreeing with the diameter 'oft-he cable 20.In order to provide adjustment or the pointer to cause it to registerwith the graduations of the scale 39 a bracket 4I) is carried onthe legof the pointer 31 and istted with an adjustingfbolt GI, The .bolt Iengages upperY face :l2 of the pressure lever 28 and will vridetherealongas the lever 28 swings.

In .operation of thepresent .invention the testing Vtool is constructedand assembled asshown in Fig. 1, vafter which the squared V pin carriedbythe head of the wrench .32 is lpositioned within the squared `opening`3I vat the `end of the 'lever extension 3D. When the set torque wrench3.2 has .been assembled with the testing tool, as shown inFig. 1, the,handle AI'Il ,of the testing tool and `the 1handle .3,6 .of the.wrenchwill be substantially parallel. 'The handle of the Wrench may beswungoutwardly to ,lower .the lower saddle.

block 24 so thai-,the -cable .20 .to be Ktested ,may be .laid in the.grooves I9 vof the upper .saddle blocks Il and J8, `after which .theAhandleof .the wrench 32 .may .beswungin Ythe ..direction..,of ,thearrow. a shown in Fig. .1. This willbring the arcuate groove .25 ofthefsaddle blocklll .in `contact with theY cableZIl. Y'.Uhe tensionofthecable may ,then-be tested. It .should be explained-that the set.torque wrench has A.been adjusted by v.manipulationof .the plug33sothat Vthe Ispring within the handleof thewrench willbeunderfa .desiredtension, ,as ,indicated'by .the pointof register of the .indicator .pin.3,5 with ,the-calibrations of the scale 33. Thus, .assuming that eachcalibration indicates ten pounds, it wvillbe evident that by When thistakes place the pointer springof the .tool theindicating pin 35 wilLmovealong the -slotted lopening 35 toward the Zero point.

In performing a testing 'operation it will be assumed, by way ofexample, that the -wrenchis set fora torque .load of sixtyfpounds. Thewrench is then applied .to the lever arm 3l) andthe -handle of thewrench 3.2 and the "handle I0 of the testing tool then are forced towardeach other. As this -takes place torque is imparted Ythrough the wrench32 to the free end of the lever extension .33. This tends to :swing thepressure lever .2:8 vin the direction `of the Aarrow b and forces the.saddle ,block 24 Vagainst the cable -23 atfthe opposite sides of theIPOints of contact of the -cable with .the saddle blocks `I'l and I8.The

result will .be that the tension of the cable 2.9.

will tend to resist the force of the saddle .block 24 ,as thesaddleV191001124 moves to ilex thelength of cable forminga span between thesaddle bloclis 4 I1 and I8. As the tension of this length of cableresists movement of the saddle block 24 the lever 28 will be heldagainst rotation on its pivot 29, and the wrench body and handle 32 willbe caused to rotate around the head of the wrench which will be heldimmovable by the squared pin ex-V tending into the opening 3| of thelever extension 3B. As the wrench handlev rotates the mechanism withinthe wrench `will force .the index pointer35along '.the slotted opening3.6and toward the zero graduation. Assuming that the 'pointer 35 reachesthe zero graduation a force of sixty pounds will have been applied tothe free end-of the lever extension 30 and a suitable force vwill .havebeen applied to the saddle block 24 :dueto the leverage existing betweenthe lever arms 30 and 28. If the pointer 35 moves from its setpositionto the zero graduation on the scale -34 this will indicate thatthe cable 20 is under a minimum tension represented by the ln-l itiallyset position of the pointer 35.011 the wrench 32, After the ltest hasbeen made kthe wrench can be removed so that it is ready for any otheruse desired, and due ,to'the fact that the 'testing toolis rugged inconstruction it may be vplaced away without fear of vaccidental damageand without the parts losing their adjustment.

Some ,types of set torque wrenches may have an element in them whichtends to break when a predetermined amount of torque force 1hasioeenapplied to the torque Wrench and isbeing resisted by an element rotatedby v the wrench. When this type of wrench is usedthe desired'ten; siontest may be made inthe same manner as' herein described, with vtheexception 'that'jwhen the tension of .the cable resists apredcte'rminedamount .of forcethewrench will break and indicate that the vcab'lehas atAleast the f desired amount vof tension. l i It will ,thus be .seen thatthe testing 'toolhere disclosed .is simple in .construction ,and or 'adesign wh'ich makes it N.possible for ,the 'tool vtolte easily adjustedfor yuse. in testing the ltension of cables of 4various diameters, thesaid r,tool being operable in connection with: a torque .setjw-renchwhereby expensiveV and delicate testing equipment is eliminated. Y

While we have shown the ,preferred form lofour invention as .now knownto us., it will -be understood that various changesinaybe made in com.-`bination, construction and arrangement oi parts by .those skilledintheart, without departing. from the spirit of our inventionas claimed.

Having' thus described our invention` .what .we claim ,and .desire tosecure by Lettersglatent is.:-

'l. vlVleansi-or testing a cablesaid means 4acting in combination witha.v set torque wrench,.andin-l said xed elements, a bell crank pivotallymounted on the frame `of said 4tool and-oarryingthe movable element atthe .fend of :one .lever 'armthereof, the end -of the vopposite leve-rarm :receiving a rotatable member .ofa set torque wrenuh,

whereby when the handle o the'w-renchz-.andthetool are forced toward.each other the ,movable 2, A tensiometer vattachment ,tor a-setltorquez therewith, a pair of relatively xed saddle blocks spacedfrom each other on said plate to engage one side of a cable to betested, a movable saddle block to engage the opposite side of a cable tobe tested, a bell crank carrying the movable saddle block at the end ofone of its arms and being pivotally mounted upon said frame plate, theopposite arm of the bell crank being designed to receive engaging meansfrom the head of the set torque wrench, whereby when an effort is madeto force the handle of the tool and the wrench toward each other therewill be a tendency to swing the bell crank on its pivot and force themovable saddle block against the cable.

3. The structure of claim 2 including a graduated scale carried upon thebody plate, and o.

6 pointer pivotally mounted upon the body plate to swing over thegraduated scale and being moved with the movable saddle block.

4. The structure of claim 2 including a graduated scale carried upon thebody plate, a pointer pivotally mounted upon the body plate to swingover the graduated scale and being moved with the movable saddle block,and means for adjusting said pointer with relation to the scale and themovable saddle block.

5. The structure of claim 2 in which the body plate is oset withrelation to its handle, whereby the handle of the Wrench will be insubstantially the same plane as the handle of the tool.

ALBERT L. MARKER. EMRIC W. BERGERE.

